When you have found the evidence, it is important to consider whether it is relevant to your patient, and if the research stands up to scrutiny. Are there any flaws in the methodology? Is the study biased in any way? You will need to know about the legitimate use of statistics and how each kind of research works.
EBM Pyramid w/ USD Resources
Pyramid of evidence, descriptions of databases.
The pyramid serves as a guideline to the hierarchy of evidence available. You may not always find the best level of evidence to answer your question. In the absence of the best evidence, you then need to consider moving down the pyramid to other types of studies.
How to Read a Paper: The Basics of Evidence Based Medicine was originally published as a series of 10 articles introducing non-experts to finding medical articles and assessing their value. It is available in hard copy, as an electronic book, and as an online article series:
Online links to original article series: How to Read a Paper by Trisha Greenhalgh